Corrugated cardboard boxes are provided with prismatic reinforcements which despite their triangular shape result in a loss of useful space in the box, as the face corresponding to the triangle's hypotenuse faces inwards, occupying considerable space.
Additionally, invention patent P 9602617, of the same applicant, describes a stackable tray for transport of perishable products and the like consisting of five independent compact cardboard parts, duly die-cut, which comprise the base, the two greater side walls the corresponding end pieces, so that the base part is provided with four slits corresponding to the corners between which a folding line allows to place upright on the base part, small vertical extensions to which are glued the side walls and end pieces, so that the parts which make up the side walls have end extensions which occupy half of each end piece, thereby forming a double wall with the independent end piece part.
Furthermore, traditional corner reinforcements are obtained by an enveloping folding of a number of sectors defined by transverse folding lines which are extensions of the end pieces, such that this enveloping construction of the reinforcements results in rectangular prisms formed by double and triple walls which envelop each other, as stated before.
However, although the box described in said P 9602617 has a considerable resistance to both stacking and humidity, and is efficient in its function, it suffers from two problems and disadvantages, namely that the prism reinforcements of the corners are obtained at the same station as the assembly and gluing of the box, and that said prism reinforcements, due to their enveloping triangular shape, occupy a considerable space which results in a corresponding reduction in the box capacity.
Naturally, if the corner reinforcements arrived at the box assembly station already formed, the production rate would increase, while for the second case it would be desirable to minimise the volume occupied by the prismatic corner reinforcements.
In addition, said tray or box also loses internal capacity due to the considerable size of the reinforcement surface corresponding to the hypotenuse of each rectangular prism in each corner reinforcement.